The data used for control includes data periodically exchanged between a controlling device and a controlled device. The controlling device and the controlled device are connected to a communication device forming a network and exchange data via the network. There is also a configuration in which one or both of the controlling device and the controlled device include a circuit and the like corresponding to the communication device and are directly connected to the network. Transmission with a low delay is required for control data that is data used for control.
Patent Literature 1 discloses an inventive technique regarding a system for transmitting control data for an industrial machine. In the inventive technique disclosed in Patent Literature 1, a transmission cycle is set which is formed including a first range for performing data transmission for periodically made real-time communication, that is, real-time control and a second range for performing communication other than the periodically made real-time communication, so as to allow the real-time communication to be prevented from being affected by the other communication.